A dealer sells two laptops at the rate of Rs. 4680 per laptop. On one he gains 30 percent and on the other he suffers a loss of 40 percent. What is his percentage loss in the whole transaction?

Correct option is D

Given:
Selling price of each laptop = Rs. 4,680
Profit on the first laptop = 30%
Loss on the second laptop = 40%
Concept Used:

​$$\text{Percentage Loss} = \left( \frac{\text{Loss}}{\text{Total CP}} \right) \times 100$$​​

Solution:
$$SP = CP + \text{Profit}$$​​
$$4,680 = CP_1 + 0.30 \times CP_1$$​​
$$4,680 = 1.30 \times CP_1$$​​
$$CP_1 = \frac{4,680}{1.30} = 3,600 \text{ Rs.}$$​​
$$SP = CP - \text{Loss}$$​​
$$4,680 = CP_2 - 0.40 \times CP_2$$​​
$$4,680 = 0.60 \times CP_2$$​​
$$CP_2 = \frac{4,680}{0.60} = 7,800 \text{ Rs.}$$​​
$$\text{Total CP} = CP_1 + CP_2 = 3,600 + 7,800 = 11,400 \text{ Rs.}$$​​
$$\text{Total SP} = 4,680 \times 2 = 9,360 \text{ Rs.}$$​​
$$\text{Loss} = \text{Total CP} - \text{Total SP} = 11,400 - 9,360 = 2,040 \text{ Rs.}$$​​
$$\text{Percentage Loss} = \left( \frac{\text{Loss}}{\text{Total CP}} \right) \times 100$$​​
$$\text{Percentage Loss} = \left( \frac{2,040}{11,400} \right) \times 100 \approx 17.89\%$$​​
The dealer's overall percentage loss in the whole transaction is approximately 17.89%.